Methods and systems for controlling bubble size and bubble decay rate in foamed glass produced by a submerged combustion melter

ABSTRACT

Methods and systems for controlling bubble size and bubble decay rate of glass foams formed during submerged combustion melting. Flowing a molten mass of foamed glass comprising molten glass and bubbles entrained therein into an apparatus downstream of a submerged combustion melter. The downstream apparatus has a floor, a roof, and a sidewall structure connecting the floor and roof. The foamed glass has glass foam of glass foam bubbles on its top surface, and the downstream apparatus defines a space for a gaseous atmosphere above and in contact with the glass foam. The downstream apparatus includes heating components to heat or maintain temperature of the foamed glass. Adjusting composition of the atmosphere above the glass foam, and/or contacting the foam with a liquid or solid composition controls bubble size of the glass foam bubbles, and/or foam decay rate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application may be related to the following United Statesnon-provisional patent applications assigned to the assignee of thepresent application which are all incorporated by reference herein: U.S.Ser. No. 12/817,754, filed Jun. 17, 2010; U.S. Ser. Nos. 13/267,990,13/268,028, 13/268,098, and 13/268,130, all four filed Oct. 7, 2011;U.S. Ser. No. 13/458,211, filed Apr. 27, 2012; U.S. Ser. Nos. 13/493,170and 13/493,219, both filed Jun. 11, 2012; U.S. Ser. No. 13/540,771,filed Jul. 3, 2012. U.S. patent applications identified as AttorneyDocket Nos. 8144-1, 8144-2, 8147 and 8154 are being filed on even dateherewith.

BACKGROUND INFORMATION

1. Technical Field

The present disclosure relates generally to the field of combustionfurnaces and methods of use to produce glass, and more specifically tomethods and systems to control bubble size and/or foam decay rate inglass handling equipment downstream of a submerged combustion melter.

2. Background Art

A submerged combustion melter (SCM) may be employed to melt glass batchmaterials to produce molten glass by passing oxygen, oxygen-enrichedmixtures, or air along with a liquid or gaseous fuel, or particulatefuel in the glass batch, directly into a molten pool of glass usuallythrough burners submerged in a glass melt pool. The introduction of highflow rates of products of combustion of the oxidant and fuel into themolten glass, and the expansion of the gases cause rapid melting of theglass batch and much turbulence, and possibly foaming.

While traditional, non-submerged combustion melters may to a lesserdegree suffer from the problems discussed herein (and therefore maybenefit from one or more aspects of this disclosure), molten glassproduced by an SCM is typically about 30 percent void fraction or morewith small bubbles that may have a range of sizes distributed throughoutthe molten mass of glass. These are referred to herein as “entrainedbubbles.” This void fraction is much higher than molten glass producedby traditional, non-submerged combustion melters. For good glass fiberproduction from an SCM or other melter, it is preferred that the bubblesbe allowed to coalesce and rise to the surface giving good, clean,well-defined molten glass in lower regions of downstream channels andforehearths to be delivered to a forming operation, such as forcontinuous e-glass fibers. With regard to SCMs, attempts to reduce thefoam through SCM process adjustments, such as use of helium and steam toscavenge and consolidate bubbles, sonic methods to consolidate bubbles,vacuum to increase bubble size, and centrifugal force have not met withcomplete success in reducing foam from an SCM to an acceptable amount.Certain SCMs and/or flow channels may employ one or more high momentumburners, for example, to impinge on portions of a foam layer. Highmomentum burners are disclosed assignee's patent application U.S. Ser.No. 13/268,130, filed Oct. 7, 2011. Various methods and systems forde-stabilizing the foam layer in equipment downstream of an SCM areproposed in assignee's patent applications, U.S. Ser. Nos. ______ and______, both filed on even date herewith (Attorney Docket Nos. 8144-1and 8144-2). On the other hand, for production of foam glass productsfrom an SCM, it may be preferred to maintain the bubbles in theirentrained state.

It would be an advance in the glass manufacturing art if foams producedduring melting of glass-forming materials, and in particular foamsproduced during submerged combustion melting of glass-forming materials,could be controlled in equipment downstream of the SCM.

SUMMARY

In accordance with the present disclosure, methods and systems aredescribed that allow foams produced during submerged combustion meltingof glass-forming materials to be controlled in equipment downstream ofthe SCM. While the methods and systems of the present disclosure mayalso be applicable to non-submerged combustion melters, the highlyturbulent molten foamed glass formed in SCMs is a particular target ofthe methods and systems of the present disclosure.

A first aspect of the disclosure is a method comprising:

flowing a molten mass of foamed glass comprising molten glass andbubbles entrained therein into an apparatus downstream of a submergedcombustion melter, the downstream apparatus comprising a floor, a roof,and a sidewall structure connecting the floor and roof, the foamed glasshaving glass foam comprising glass foam bubbles on at least a portion ofa top surface of the foamed glass, the downstream apparatus defining aspace for a gaseous atmosphere above and in contact with the glass foam;

heating or maintaining temperature of the foamed glass in the downstreamapparatus; and

controlling bubble size of the glass foam bubbles in the foamed glass bycontrolling composition of the atmosphere above the glass foam in thedownstream apparatus.

A second aspect of the disclosure is a method comprising:

flowing a molten mass of foamed glass comprising molten glass andbubbles entrained therein into an apparatus downstream of a submergedcombustion melter, the downstream apparatus comprising a floor, a roof,and a sidewall structure connecting the floor and the roof, the foamedglass having glass foam comprising glass foam bubbles on at least aportion of a top surface of the foamed glass, the downstream apparatusdefining a space for a gaseous atmosphere above and in contact with theglass foam;

heating or maintaining temperature of the foamed glass using onlycombustion heating comprising one or more non-submerged oxy-fuelcombustion burners positioned in the sidewall structure and/or the roofof the downstream apparatus, the non-submerged oxy-fuel combustionburners contributing to production of the atmosphere above the glassfoam; and

controlling bubble size of the glass foam bubbles by bubbling acomposition comprising an oxygenated sulfur compound and optionallyoxygen below a level of the foamed glass in the downstream apparatus,thereby stabilizing size of the glass foam bubbles and a foam decayrate, with the proviso that if oxygen is present in the composition, themolar ratio of oxygenated sulfur compound to oxygen ranges from about3:1 to about 0.5:1.

A third aspect of the disclosure is a method comprising:

flowing a molten mass of foamed glass comprising molten glass andbubbles entrained therein into an apparatus downstream of a submergedcombustion melter, the downstream apparatus comprising a floor, a roof,and a sidewall structure connecting the floor and the roof, the foamedglass having glass foam comprising glass foam bubbles on at least aportion of a top surface of the foamed glass, the downstream apparatusdefining a space for a gaseous atmosphere above and in contact with theglass foam;

heating or maintaining temperature of the foamed glass in the downstreamapparatus; and

controlling a foam decay rate of the glass foam bubbles by:

-   -   i) adjusting composition of at least a portion of the gaseous        atmosphere; or    -   ii) contacting a top surface of the glass foam with a liquid or        solid composition or combination thereof; or    -   iii) combination of (i) and (ii).

A fourth aspect of the disclosure is a method comprising:

flowing a molten mass of foamed glass comprising molten glass andbubbles entrained therein into an apparatus downstream of a submergedcombustion melter, the downstream apparatus comprising a floor, a roof,and a sidewall structure connecting the floor and roof, the foamed glasshaving glass foam comprising glass foam bubbles on at least a portion ofa top surface of the foamed glass, the downstream apparatus defining aspace for a gaseous atmosphere above and in contact with the glass foam;

heating or maintaining temperature of the foamed glass in the downstreamapparatus using only combustion heating comprising one or morenon-submerged oxy-fuel combustion burners positioned in correspondingapertures in the sidewall structure and/or the roof of the downstreamapparatus, the non-submerged oxy-fuel combustion burners producingcombustion products contributing to formation of the atmosphere abovethe glass foam; and

increasing foam decay rate of the glass foam bubbles by dropping amixture of alkali metal chalcogen particles and glass particles throughthe gaseous atmosphere and onto at least a portion of the glass foamfrom one or more sources outside of and fluidly connected to thedownstream apparatus, the glass particles having same or similarcomposition as the foamed glass.

A fifth aspect of the disclosure is a method comprising:

flowing a molten mass of foamed glass comprising molten glass andbubbles entrained therein into an apparatus downstream of a submergedcombustion melter, the downstream apparatus comprising a floor, a roof,and a sidewall structure connecting the floor and roof, the foamed glasshaving glass foam comprising glass foam bubbles on at least a portion ofa top surface of the foamed glass, the downstream apparatus defining aspace for a gaseous atmosphere above and in contact with the glass foam;

heating or maintaining temperature of the foamed glass in the downstreamapparatus using only combustion heating comprising one or morenon-submerged oxy-fuel combustion burners positioned in correspondingapertures in the sidewall structure and/or the roof of the downstreamapparatus, the non-submerged oxy-fuel combustion burners producingcombustion products contributing to formation of the atmosphere abovethe glass foam; and

increasing foam decay rate of the glass foam bubbles by fully saturatingthe gaseous atmosphere with water by injecting a water vapor sprayand/or steam from a first source outside of and fluidly connected to thedownstream apparatus, and dripping water through the gaseous atmosphereand onto at least a portion of the glass foam from a second sourceoutside of and fluidly connected to the downstream apparatus.

Other aspects of the disclosure include systems for carrying out theabove methods.

Methods and systems of this disclosure will become more apparent uponreview of the brief description of the drawings, the detaileddescription of the disclosure, and the claims that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

The manner in which the objectives of the disclosure and other desirablecharacteristics can be obtained is explained in the followingdescription and attached drawings in which:

FIG. 1 is a schematic side elevation view, partially in cross-section,of one system embodiment in accordance with the present disclosure, andFIG. 2 is a schematic transverse cross-section of the embodiment in FIG.1;

FIGS. 3, 4, 5, 6, 7 and 8 are schematic transverse cross-sectional viewsof six alternative embodiments of the system of FIGS. 1 and 2;

FIG. 9 is a schematic side elevation view, partially in cross-section,of another system embodiment in accordance with the present disclosure,and FIG. 10 is a schematic transverse cross-section of the embodiment inFIG. 9;

FIGS. 11, 12, 13, 14, and 15 are logic diagrams of five methodembodiments of the present disclosure; and

FIGS. 16A-G, 17A-C, and 18A-E illustrate graphically some experimentalresults in accordance with the present disclosure.

It is to be noted, however, that the appended drawings of FIGS. 1-10 maynot be to scale and illustrate only typical embodiments of thisdisclosure, and are therefore not to be considered limiting of itsscope, for the disclosure may admit to other equally effectiveembodiments.

DETAILED DESCRIPTION

In the following description, numerous details are set forth to providean understanding of the disclosed systems and methods. However, it willbe understood by those skilled in the art that the systems and methodscovered by the claims may be practiced without these details and thatnumerous variations or modifications from the specifically describedembodiments may be possible and are deemed within the claims. All U.S.published patent applications and U.S. patents referenced herein arehereby explicitly incorporated herein by reference. In the eventdefinitions of terms in the referenced patents and applications conflictwith how those terms are defined in the present application, thedefinitions for those terms that are provided in the present applicationshall be deemed controlling.

As explained briefly in the Background, molten glass produced by an SCMis typically about 30 percent void fraction or more with small bubblesdistributed throughout the molten mass of glass, and this void fractionis much higher than molten glass produced by traditional, non-submergedcombustion melters. Attempts to reduce the foam through SCM processadjustments, for example to produce good glass fibers from an SCM, havenot met with complete success in reducing foam from an SCM to anacceptable amount. On the other hand, for production of foam glassproducts from an SCM, it may be preferred to maintain the bubbles intheir entrained state.

The inventors herein have discovered that the size of bubbles collectingat the top surface of the molten glass from an SCM forming a foam layer,and the rate at which the bubbles burst upon reaching a clearlydiscernable glass surface, referred to herein as the “foam decay rate”,may be controlled in apparatus downstream of the SCM. To produce glassproducts having low or no voids, and for good heat penetration from heatsources over the foam and into the molten glass, the foam decay rate iscontrolled in apparatus downstream of the SCM to be as fast as possible.On the other hand, for production of foam glass products from an SCM,the foam decay rate in apparatus downstream of the SCM is controlled tobe slow and the size of the bubbles within the foam may be influenced orcontrolled. A slower foam decay rate insures production of a foam glassproduct, all other parameters being equal, and control of the bubblesize within the foam may enable production of foam glass products ofspecific strength, insulating properties, and/or density.

Various terms are used throughout this disclosure. “Submerged” as usedherein means that combustion gases emanate from a combustion burner exitthat is under the level of the molten glass, and “non-submerged” meansthat combustion gases do not emanate from combustion burner exits underthe level of molten glass, whether in the SCM or downstream apparatus.Both submerged and non-submerged burners may be roof-mounted,floor-mounted, wall-mounted, or any combination thereof (for example,two floor mounted burners and one wall mounted burner). “SC” as usedherein means “submerged combustion” unless otherwise specifically noted,and “SCM” means submerged combustion melter unless otherwisespecifically noted.

The term “composition” includes one or more gases, one or more liquidsor solids that may evolve a gas or become gaseous under the hightemperature conditions associated with submerged combustion melting, oneor more particulate solids, and combinations of thereof, includingslurries, mixtures of a gas and solid particles, and the like.

The terms “foam” and “foamy” include froths, spume, suds, heads, fluffs,fizzes, lathers, effervesces, layer and the like. The term “bubble”means a thin, shaped, gas-filled film of molten glass. The shape may bespherical, hemispherical, rectangular, polyhedral, ovoid, and the like.The gas or “bubble atmosphere” in the gas-filled SC bubbles may compriseoxygen or other oxidants, nitrogen, combustion products (including butnot limited to, carbon dioxide, carbon monoxide, NO_(x), SO_(x), H₂S,and water), reaction products of glass-forming ingredients (for example,but not limited to, sand (primarily SiO₂), clay, limestone (primarilyCaCO₃), burnt dolomitic lime, borax and boric acid, and the like.Bubbles may include solids particles, for example soot particles, eitherin the film, the gas inside the film, or both. The term “glass foam”means foam where the liquid film comprises molten glass. “Glass level”means the distance measured from the bottom of a downstream apparatus tothe upper liquid level of the molten glass, and “foam level” means thedistance measured from the top of the atmosphere above the foam layer tothe upper surface of the foam layer. “Foam height” (equivalent to foamthickness) is the distance measured between the glass level and foamlevel.

As used herein the term “combustion” means deflagration-type combustionunless other types of combustion are specifically noted, such asdetonation-type combustion. Deflagration is sub-sonic combustion thatusually propagates through thermal conductivity; hot burning materialheats the next layer of cold material and ignites it. Detonation issupersonic and primarily propagates through shock. As used herein theterms “combustion gases” and “combustion products” means substantiallygaseous mixtures of combusted fuel, any excess oxidant, and combustionproducts, such as oxides of carbon (such as carbon monoxide, carbondioxide), oxides of nitrogen, oxides of sulfur, and water, whether fromdeflagration, detonation, or combination thereof. Combustion productsmay include liquids and solids, for example soot and unburned ornon-combusted fuels.

“Oxidant” as used herein includes air and gases having the same molarconcentrations of oxygen and nitrogen as air (synthetic air),oxygen-enriched air (air having oxygen concentration greater than 21mole percent), and “pure” oxygen, such as industrial grade oxygen, foodgrade oxygen, and cryogenic oxygen. Oxygen-enriched air may have 50 molepercent or more oxygen, and in certain embodiments may be 90 molepercent or more oxygen.

The term “fuel”, according to this disclosure, means a combustiblecomposition comprising a major portion of, for example, methane, naturalgas, liquefied natural gas, propane, hydrogen, steam-reformed naturalgas, atomized hydrocarbon oil, combustible powders and other flowablesolids (for example coal powders, carbon black, soot, and the like), andthe like. Fuels useful in the disclosure may comprise minor amounts ofnon-fuels therein, including oxidants, for purposes such as premixingthe fuel with the oxidant, or atomizing liquid or particulate fuels. Asused herein the term “fuel” includes gaseous fuels, liquid fuels,flowable solids, such as powdered carbon or particulate material, wastematerials, slurries, and mixtures or other combinations thereof.

The sources of oxidant and fuel may be one or more conduits, pipelines,storage facility, cylinders, or, in embodiments where the oxidant isair, ambient air. Oxygen-enriched oxidants may be supplied from apipeline, cylinder, storage facility, cryogenic air separation unit,membrane permeation separator, or adsorption unit such as a vacuum swingadsorption unit.

The term “downstream apparatus” means a container, channel or conduitdefined at least by a floor and a wall structure extending upwards fromthe floor to form a space in which molten glass may be present, whetherflowing or not. In certain embodiments the downstream apparatus willinclude a roof and a wall structure connecting the floor and roof. Thedownstream apparatus may have any operable cross-sectional shape (forexample, but not limited to, rectangular, oval, circular, trapezoidal,hexagonal, and the like) and any flow path shape (for example, but notlimited to, straight, zigzag, curved, and combinations thereof). Incertain systems and methods the downstream apparatus may be a flowchannel selected from the group consisting of a conditioning channel, adistribution channel, and a forehearth.

Downstream apparatus, as well as conduits used in burners and devicesfor delivery of compositions useful in systems and methods of thepresent disclosure may be comprised of metal, ceramic, ceramic-linedmetal, or combination thereof. Suitable metals include stainless steels,for example, but not limited to, 306 and 316 steel, as well as titaniumalloys, aluminum alloys, and the like. Suitable materials for theglass-contact refractory, which may be present in SC melters and flowchannels, and refractory burner blocks (if used), include fused zirconia(ZrO₂), fused cast AZS (alumina-zirconia-silica), rebonded AZS, or fusedcast alumina (Al₂O₃). The particular system and method, downstreamapparatus, burner geometry, composition delivery system, and type ofglass to be produced may all dictate the choice of a particularmaterial, among other parameters.

Certain submerged and non-submerged combustion burners, certaincomponents in and/or protruding through one or more of the floor, roof,and sidewall structure configured to heat or maintaining temperature ofthe foamed glass, certain apparatus for delivering a composition throughone or more apertures in the sidewall structure and/or the roof foradmitting one or more compositions into the atmosphere, and certainportions of the sources of the compositions fluidly connected to theapertures useful in systems and methods of this disclosure may befluid-cooled, and may include first and second (or more) concentricconduits. In the case of burners, the first conduit may be fluidlyconnected at one end to a source of fuel, the second conduit may befluidly connected to a source of oxidant, and a third substantiallyconcentric conduit may connect to a source of cooling fluid.

Certain systems of this disclosure may comprise one or morenon-submerged burners. Suitable non-submerged combustion burners maycomprise a fuel inlet conduit having an exit nozzle, the conduit andnozzle inserted into a cavity of a ceramic burner block, the ceramicburner block in turn inserted into either the roof or the wallstructure, or both the roof and wall structure of the downstreamapparatus.

In certain systems, one or more burners may be adjustable with respectto direction of flow of the combustion products. Adjustment may be viaautomatic, semi-automatic, or manual control. Certain system embodimentsmay comprise a burner mount that mounts the burner in the wallstructure, roof, or floor of the downstream apparatus comprising arefractory, or refractory-lined ball joint. Other burner mounts maycomprise rails mounted in slots in the wall or roof. In yet otherembodiments the burners may be mounted outside of the downstreamapparatus, on supports that allow adjustment of the combustion productsflow direction. Useable supports include those comprising ball joints,cradles, rails, and the like.

In certain systems and methods of the present disclosure, the downstreamapparatus may comprise a flow channel comprising a series of sections,and may comprise one or more skimmers and/or impingement (high momentum)burners, such as described in assignee's co-pending application U.S.Ser. No. 13/268,130, filed Oct. 7, 2011, and Ser. No. 13/493,170, filedJun. 11, 2012. Certain systems and methods of the present disclosure mayutilize measurement and control schemes such as described in assignee'sco-pending application U.S. Ser. No. 13/493,219, filed Jun. 11, 2012,and/or feed batch densification systems and methods as described inassignee's co-pending application U.S. Serial No. 13540704, filed Jul.3, 2012. Certain systems and methods of the present disclosure mayutilize one or more retractable devices for delivery of treatingcompositions such as disclosed in assignee's co-pending application,U.S. Ser. No. ______, filed on even date herewith (Attorney Docket No.8147). Certain systems and methods of the present disclosure may utilizeone or more nozzles for delivery of treating compositions such asdisclosed in assignee's co-pending application U.S. Ser. No. ______,filed on even date herewith (Attorney Docket No. 8144-1).

Certain systems and methods of this disclosure may be controlled by oneor more controllers. For example, burner (flame) temperature may becontrolled by monitoring one or more parameters selected from velocityof the fuel, velocity of the primary oxidant, mass and/or volume flowrate of the fuel, mass and/or volume flow rate of the primary oxidant,energy content of the fuel, temperature of the fuel as it enters theburner, temperature of the primary oxidant as it enters the burner,temperature of the effluent, pressure of the primary oxidant enteringthe burner, humidity of the oxidant, burner geometry, combustion ratio,and combinations thereof. Certain systems and methods of this disclosuremay also measure and/or monitor feed rate of batch or other feedmaterials, such as glass batch, cullet, mat or wound roving andtreatment compositions, mass of feed, and use these measurements forcontrol purposes. Exemplary systems and methods of the disclosure maycomprise a controller which receives one or more input parametersselected from temperature of melt, composition of bubbles and/or foam,height of foam layer, glass level, foam level, and combinations thereof,and may employ a control algorithm to control combustion temperature,flow rate and/or composition of compositions to control foam decay rateand/or glass foam bubble size, and other output parameters based on oneor more of these input parameters.

Specific non-limiting system and method embodiments in accordance withthe present disclosure will now be presented in conjunction with theattached drawing figures. The same numerals are used for the same orsimilar features in the various figures. In the views illustrated in thedrawing figures, it will be understood in each case that the figures areschematic in nature, and certain conventional features may not beillustrated in all embodiments in order to illustrate more clearly thekey features of each embodiment. The geometry of the downstreamapparatus is illustrated generally the same in the various embodiments,but that of course is not necessary. Certain systems and methods may bedescribed as comprising an SCM and one or more downstream apparatusreceiving flow of molten glass and foam from the SCM.

FIG. 1 is a schematic side elevation view, partially in cross-section,of one system embodiment 100 in accordance with the present disclosure,and FIG. 2 is a schematic transverse cross-section of embodiment 100. Inall of the drawing figures where an SCM is illustrated, such as at 2 inFIG. 1, the SCM is illustrated in dashed lines, indicating that the SCMis not, strictly speaking, a part of every system and method of thepresent disclosure. However, certain systems and methods may bedescribed as comprising an SCM and one or more downstream apparatusreceiving flow of molten glass and foam from the SCM. Molten glass andfoam produced in SCM 2 flow into a forehearth or other downstreamapparatus via a melter exit structure 3, also illustrated in dashedlines, fluidly connecting SCM 2 and the downstream apparatus, thedownstream apparatus having a roof 4, floor 6, and sidewall structure 8connecting roof 4 with floor 6. An exit structure, 3, fluidly (and incertain embodiments mechanically) connects SCM 2 with the downstreamapparatus. Floor 6 and a portion of sidewall structure 8 define a firstspace 10 for containing a flowing or non-flowing molten mass of glass14. A second space 12 is defined by roof 4 and another portion ofsidewall structure 8, and confines an atmosphere 18 above and in contactwith a glass foam layer 16 floating on top of molten glass 14. Moltenglass 14 includes a plurality of entrained bubbles 15, and glass foamlayer 16 includes a plurality of glass foam bubbles 17. The downstreamapparatus includes at least one inlet aperture 20 for receiving moltenmass of glass 14 and foam 16. One or more other apertures 22 in roof 4and/or sidewall structure 8 may be provided for heat sources, which maybe either combustion burners, electrical heating elements, or somecombination thereof. One or more other apertures 24 in roof 4 and/orsidewall structure 8 may be provided for introducing one or morecompositions into the downstream apparatus, as will now be discussed inmore detail. The schematic transverse cross-section of embodiment 100 ofFIG. 2 illustrates how various levels of moisture may be maintained inatmosphere 18. Apertures 24 a, 24 f allow positioning of water sprayersor steam lances 34 a, 34 b, respectively; aperture 24 b allowsconnection of a source 26 of dry ambient air or dry synthetic air;aperture 24 c allows connection of a source of ambient air through useof a fan 28. Finally, optional apertures 24 d, 24 e may be provided forintroduction of other moisture-laden compositions or dry compositions.Manipulation of the sources allows manipulation of the moisture contentor humidity of atmosphere 18. As indicated in the Examples, highermoisture concentrations tend to have the effect of destabilizing glassfoam bubbles 17 by increasing their size until they burst, and producehigher foam decay rates.

FIGS. 3, 4, 5, 6, 7 and 8 are schematic transverse cross-sectional viewsof six alternative embodiments of the system of FIGS. 1 and 2.Embodiment 200 illustrated schematically in FIG. 3 includes threeapertures 22 a, 22 b, and 22 c in roof 4, each accommodating respectiveair-fuel burners 32 a, 32 b, and 32 c. Apertures 22 d and 22 eaccommodate respective oxy-fuel burners 30 a, 30 b in sidewall structure8. Embodiment 200 also allows adjustment of moisture concentration ofatmosphere 18, as well as possibly other gases, such as oxides of carbonand sulfur, depending on the fuels used. Since oxy-fuel burnerscombusting natural gas produce combustion products having relativelycontinuous moisture content of about 58 mole percent, the moisturecontent of atmosphere 18 may be reduced slightly using the air-fuelburners in conjunction with the oxy-fuel burners. Shutting off theoxy-fuel burners while maintaining operation or increasing the output ofthe air-fuel burners would produce a lower amount of moisture isatmosphere 18, while shutting off the air-fuel burners and increasingthe output of the oxy-fuel burners would have the opposite effect. Thisis one of many embodiments where the heating or maintaining temperatureof the molten mass comprises combusting an oxidant with a fuel toproduce combustion products. The combustion products mix with atmosphere18. The oxidant may be selected from the group consisting of ambientair, synthetic air, oxygen-enriched ambient air, oxygen-enrichedsynthetic air, and compositions comprising more than about 95 molepercent oxygen.

Turning now to FIG. 4, embodiment 300 illustrated schematically in FIG.4 includes two or more water vapor or steam lances, 34 a, 34 b, as wellas sources 36 a, 36 b, and 36 c of liquid, such as liquid water, that isdripped onto glass foam 16. Valves 43 in one or more, or each conduitleading from sources 36 a, 36 b, and 36 c allow control of the amountand drop size of drops of liquid 37, which fall through atmosphere 18and impact glass foam 16. In the Examples herein, embodiment 300produced the highest foam decay rate when liquid water was used. Theflow rate of water vapor or steam may first be adjusted to provide thehighest concentration of moisture in atmosphere 18 that may be obtainedusing those sources, after which the water or other liquid drip may beinitiated. Alternatively, the dripping liquid may be started first, withthe water vapor or steam lancing beginning thereafter. The flow rates oreach depend upon the size of the downstream apparatus and size (volume)of atmosphere 18, as well as the exhaust system provided for thedownstream apparatus. It should be noted that in embodiments where acomposition is dropped onto, bubbled through, or otherwise added to themolten glass, the amount of composition added may range from a few gramsup to a few kilograms per minute. The intention is to use a small amountso that the final glass chemistry is not affected, but that effectivelyde-stabilizes or stabilizes the foam as the case may be. The alternativeis to formulate the glass so that the additional chemical completes thetarget chemistry. In the case of hydrated ingredients, both hydrated andnon-hydrated forms may be used.

FIG. 5 illustrates schematically another system and method embodiment400, comprising three apertures 24 a, 24 b, and 24 c, with apertures 24a and 24 c accommodating water vapor conduits and/or steam lances 34 aand 34 b. Water vapor supply conduits or steam lances 34 a, 34 b areequipped in embodiment 400 with respective sources 38 a, 38 b of liquidor solid chemical that are mixed with the water vapor and/or steam.Aperture 24 b is fluidly connected with a source 26 of dry ambient airand/or dry synthetic air 26. Suitable liquid and/or solid chemicals aredescribed herein.

FIG. 6 illustrates schematically another system and method embodiment500, which is similar to embodiment 400, but comprises four apertures 24a, 24 b, 24 c, and 24 d, with apertures 24 a and 24 d accommodatingoxy-fuel combustion burners 30 a and 30 b, and water vapor supplyconduits or steam lances 34 a, 34 b are equipped with respective sources38 a, 38 b of liquid or solid chemical that are mixed with the watervapor and/or steam. Because of the use of oxy-fuel combustion burners inembodiment 500, atmosphere 18 would have a higher concentration ofmoisture than embodiment 400 that employs dry ambient or dry syntheticair.

In embodiments such as embodiments 400 and 500, the chemical may beadded to the water vapor spray as a slurry, emulsion, or dissolved inthe water, or the chemical may be added to a flow of steam. The chemicalmay comprise one or more compounds selected from the group consisting ofalkali metal chalcogens, alkali metal carbonates, and alkaline earthcarbonates. Alums are not preferred for glass chemistry reasons. Theaddition of a trivalent metal would not serve well in the quickincorporation into the glass structure and could have a large chemicalreducing effect on the glass.

Turning now to FIG. 7, embodiment 600 illustrated schematically in FIG.7 includes at least five apertures 24 a, 24 b, 24 c, 24 d, and 24 e,with apertures 24 a and 24 e accommodating oxy-fuel combustion burners30 a, 30 b, and apertures 24 b-d accommodating sources of a gas or vaporcomprising oxides of sulfur, such as sulfur dioxide, through respectiveminor conduits 40 a, 40 b, and 40 c, with a primary or main conduit 40supplying the minor conduits. A plurality of valves 43 may be use tocontrol the amount and location of addition of the gas to atmosphere 18.During laboratory testing, embodiments using gases such as used inembodiment 600 showed a tendency to stabilize size of glass foam bubbles17. Embodiment 600 is an example of controlling the composition ofatmosphere 18 above glass foam 16 by injecting a non-combustioncomposition into at least a portion of the atmosphere from a sourceoutside of the downstream apparatus using one or more apparatuspositioned in one or more apertures the sidewall structure and/or theroof. In certain embodiments the non-combustion composition comprises 10mole percent of an oxygenated sulfur compound or less, and in certainother embodiments the non-combustion composition comprises 1 molepercent of an oxygenated sulfur compound or less.

FIG. 8 illustrates schematically another system and method embodiment700, comprising a plurality of apertures in roof 4 accommodating acorresponding plurality of minor conduits 42 a-i, and which areconfigured to direct drops of a liquid or solid composition throughatmosphere 18 and thereafter onto glass foam 16. A main or primaryheader conduit 42 supplies minor conduits 42 a-i. Apertures 24 a and 24b accommodate oxy-fuel burners 30 a, 30 b. This embodiment may afford aquite high concentration of moisture in atmosphere 18, but perhaps notas high as embodiment 300, illustrated schematically in FIG. 4. Suitablesolids may include alkali metal chalcogens. Suitable alkali metalchalcogens may be selected from the group consisting of alkali metalsulfates, alkali metal bisulfates, alkali metal sulfites, alkali metalpersulfates, alkaline earth sulfates, mixtures of two or more of these,and salts of two or more of these. Alkaline carbonates and alkalineearth carbonates or their mixtures may also be employed, which mayrelease one or more carbon oxides and may therefore produce a secondary“popping” or sudden expansion effect, further de-stabilizing ordestroying bubbles. Alkali metal chalcogens may exhibit this behavior aswell, releasing one or more sulfur oxides. Specific alkali metalchalcogens may include those selected from the group consisting ofsodium sulfate, sodium bisulfate, sodium sulfite, sodium persulfate,lithium sulfate, potassium sulfate, rubidium sulfate, caesium sulfate,double salts of two of these, and double salts of one of these withanother compound. In other embodiments, the solid particles may beinclude glass particles, such as glass cullet. In certain embodiments,the solids may comprise a mixture of alkali metal chalcogen particlesand glass particles, and the methods may comprise dropping the mixtureonto at least a portion of the top surface of the glass foam from asource outside of and fluidly connected to the downstream apparatus. Inother embodiments, the glass particles may be dropped onto the glassfoam first to form a modified glass foam, followed by dropping alkalimetal chalcogen particles onto the modified glass foam.

FIG. 9 is a schematic side elevation view, partially in cross-section,of another system embodiment 800 in accordance with the presentdisclosure, and FIG. 10 is a schematic transverse cross-section ofembodiment 800. Embodiment 800 includes oxy-fuel combustion burners 30producing combustion gases that mix with atmosphere 18, as well assupply conduits 44 for addition of non-combustion gases, such as oxidesof sulfur (in certain embodiments combined with another gas such asoxygen), under the level of the molten glass 14. As illustratedschematically in FIGS. 9 and 10, oxy-fuel combustion burners 30 may bepositioned in various locations in the downstream apparatus, forexample, burners 30 a and 30 d may be positioned upstream of burners 30b and 30 c. Similarly, gas supply conduits 44 may be variouslypositioned at the same or different downstream locations as other gassupply conduits, as well at the same or different downstream positionsas the combustion burners. The goal of embodiments such as embodiment800 is to bubble oxides of sulfur, such as sulfur dioxide, optionallymixed with oxygen, through the molten glass 14 and stabilize bubblelayer 16. This practice is advantageous when the desire is to producefoamed glass products. As noted in the view of FIG. 9, foam layer 16does not significantly change in foam height (foam thickness) as themolten mass of glass moves from left to right in the downstreamapparatus, or is held stationary. Embodiment 800 is one example of amethod and system for controlling bubble size of glass foam bubbles 17by bubbling a composition comprising an oxygenated sulfur compound andoptionally oxygen below a level of the foamed glass in the downstreamapparatus, thereby stabilizing size of the glass foam bubbles 17 and afoam decay rate. In certain embodiments, if oxygen is present in thecomposition, the molar ratio of oxygenated sulfur compound to oxygenranges from about 3:1 to about 0.5:1.

FIGS. 11, 12, 13, 14, and 15 are logic diagrams of five methodembodiments of the present disclosure. Method embodiment 900 of FIG. 11includes the steps of flowing a molten mass of foamed glass comprisingmolten glass and bubbles entrained therein into an apparatus downstreamof a submerged combustion melter, the downstream apparatus comprising afloor, a roof, and a sidewall structure connecting the floor and roof,the foamed glass having glass foam comprising glass foam bubbles on atleast a portion of a top surface of the foamed glass, the downstreamapparatus defining a space for a gaseous atmosphere above and in contactwith the glass foam, box 902. This method further comprises heating ormaintaining temperature of the foamed glass in the downstream apparatus,box 904, and controlling bubble size of the glass foam bubbles in thefoamed glass by controlling composition of the atmosphere above theglass foam in the downstream apparatus, box 906.

Method embodiment 1000 of FIG. 12 comprises flowing a molten mass offoamed glass comprising molten glass and bubbles entrained therein intoan apparatus downstream of a submerged combustion melter, the downstreamapparatus comprising a floor, a roof, and a sidewall structureconnecting the floor and the roof, the foamed glass having glass foamcomprising glass foam bubbles on at least a portion of a top surface ofthe foamed glass, the downstream apparatus defining a space for agaseous atmosphere above and in contact with the glass foam, box 1002.This method further comprises heating or maintaining temperature of thefoamed glass using only combustion heating comprising one or morenon-submerged oxy-fuel combustion burners positioned in the sidewallstructure and/or the roof of the downstream apparatus, the non-submergedoxy-fuel combustion burners contributing to production of the atmosphereabove the glass foam, box 1004. Method embodiment 1000 further includescontrolling bubble size of the glass foam bubbles by bubbling acomposition comprising an oxygenated sulfur compound and optionallyoxygen below a level of the foamed glass in the downstream apparatus,thereby stabilizing size of the glass foam bubbles and a foam decayrate, with the proviso that if oxygen is present in the composition, themolar ratio of oxygenated sulfur compound to oxygen ranges from about3:1 to about 0.5:1, box 1006

Method embodiment 1100 illustrated in FIG. 13 comprises flowing a moltenmass of foamed glass comprising molten glass and bubbles entrainedtherein into an apparatus downstream of a submerged combustion melter,the downstream apparatus comprising a floor, a roof, and a sidewallstructure connecting the floor and the roof, the foamed glass havingglass foam comprising glass foam bubbles on at least a portion of a topsurface of the foamed glass, the downstream apparatus defining a spacefor a gaseous atmosphere above and in contact with the glass foam, box1102. Method embodiment 1100 further includes heating or maintainingtemperature of the foamed glass in the downstream apparatus, box 1104.Method embodiment 1100 further includes controlling a foam decay rate ofthe glass foam bubbles, box 1106 by: i) adjusting composition of atleast a portion of the gaseous atmosphere, box 1108; or ii) contacting atop surface of the glass foam with a liquid or solid composition orcombination thereof, box 1110; or iii) combination of (i) and (ii), asdepicted in box 1112.

Method embodiment 1200 illustrated in FIG. 14 comprises flowing a moltenmass of foamed glass comprising molten glass and bubbles entrainedtherein into an apparatus downstream of a submerged combustion melter,the downstream apparatus comprising a floor, a roof, and a sidewallstructure connecting the floor and roof, the foamed glass having glassfoam comprising glass foam bubbles on at least a portion of a topsurface of the foamed glass, the downstream apparatus defining a spacefor a gaseous atmosphere above and in contact with the glass foam, box1202. The method further comprises heating or maintaining temperature ofthe foamed glass in the downstream apparatus using only combustionheating comprising one or more non-submerged oxy-fuel combustion burnerspositioned in corresponding apertures in the sidewall structure and/orthe roof of the downstream apparatus, the non-submerged oxy-fuelcombustion burners producing combustion products contributing toformation of the atmosphere above the glass foam, box 1204. Method 1200further includes increasing the foam decay rate of the glass foambubbles by dropping a mixture of alkali metal chalcogen particles andglass particles through the gaseous atmosphere and onto at least aportion of the glass foam from one or more sources outside of andfluidly connected to the downstream apparatus, the glass particleshaving same or similar composition as the foamed glass, box 1206.

Method embodiment 1300 illustrated in FIG. 15 comprises flowing a moltenmass of foamed glass comprising molten glass and bubbles entrainedtherein into an apparatus downstream of a submerged combustion melter,the downstream apparatus comprising a floor, a roof, and a sidewallstructure connecting the floor and roof, the foamed glass having glassfoam comprising glass foam bubbles on at least a portion of a topsurface of the foamed glass, the downstream apparatus defining a spacefor a gaseous atmosphere above and in contact with the glass foam, box1302. The method includes heating or maintaining temperature of thefoamed glass in the downstream apparatus using only combustion heatingcomprising one or more non-submerged oxy-fuel combustion burnerspositioned in corresponding apertures in the sidewall structure and/orthe roof of the downstream apparatus, the non-submerged oxy-fuelcombustion burners producing combustion products contributing toformation of the atmosphere above the glass foam, box 1304. Methodembodiment 1300 further includes increasing the foam decay rate of theglass foam bubbles by fully saturating the gaseous atmosphere with waterby injecting a water vapor spray and/or steam from a first sourceoutside of and fluidly connected to the downstream apparatus, anddripping water through the gaseous atmosphere and onto at least aportion of the glass foam from a second source outside of and fluidlyconnected to the downstream apparatus, box 1306.

SC burners in an SCM produce a turbulent melt comprising bubbles havinga bubble atmosphere. In general the atmosphere of the bubbles is aboutthe same from bubble to bubble, but that is not necessarily so. One ormore burners in SCM 2 may be oxy-fuel burners. SCM 2 may receivenumerous feeds through one or more inlet ports, and batch feeders maybeprovided. Other feeds are possible, such as glass mat waste, woundroving, waste materials, and the like, such as disclosed in assignee'sapplication U.S. Ser. No. 12/888,970, filed Sep. 23, 2010 (U.S.Publication No. 2012/0077135, Mar. 29, 2012).

Many of the system and method embodiments of the present disclosure mayinclude valves and appropriate valve controls (not illustrated) to pulseor oscillate flow of fuel and/or oxidant to burners. The pulsing may berandom or non-random, and may provide certain benefits, such as reducedNOx emissions. The principle and the various methods of implementationare broadly described in U.S. Pat. Nos. 4,846,665, 5,302,111, and5,522,721 and U.S. Publication No. 2006/0177785. The main idea is topuke the flow of fuel, or oxidant being supplied to at least one burnerof the furnace, to generate successive fuel-rich and fuel-lean zones ina flame. In certain embodiments, the flow rate of a main or primaryoxidant is controlled by a main oxidant flow rate control unit, andoscillating combustion is generated by oscillating the fuel flow with anoscillating valve and combusting the oscillating fuel with the mainoxidant adjacent the burner to produce combustion products.

In embodiments employing water vapor injectors and/or steam lances, andembodiments where gaseous, liquid, or solid compositions, or mixturesthereof, are injected (not dropped) into atmosphere 18, one or morenozzles may extend through respective apertures in the downstreamapparatus, and be supplied by respective supply conduits. Suitablenozzles for use in systems of the present disclosure includesingle-fluid nozzles and multiple-fluid nozzles, and representativeexamples are schematically illustrated in assignee's co-pendingapplication U.S. Ser. No. ______, filed on even date herewith (AttorneyDocket No. 8144). Suitable single-fluid nozzles may include, but are notlimited to, plain orifice type nozzles, which includes a nozzle bodydefining a cavity, and having an exit end comprising an orifice.Suitable single-fluid nozzles may also include shaped orifice nozzlescomprising a nozzle body and cavity, and further comprising a shapedbody portion defining a central passage leading fluid or slurry to ahemispherical inlet that expands into a V-notch exit, which then routesfluid or slurry through a cylindrical region, and finally out exit end.The hemispherical shaped inlet and a “V” notched outlet to cause theflow to spread out on the axis of the V notch and produce a relativelyflat fan spray.

Other suitable single-fluid nozzles may include surface impingementfluid nozzles comprising two or more simple orifices which route fluidor slurry to impinge on a conical impact surface or other shaped impactsurface and form a conical spray. A surface impingement nozzle causes astream of liquid to impinge on a surface resulting in a sheet of liquidthat breaks up into drops. Yet other suitable single-fluid nozzles mayinclude pressure-swirl spray nozzles comprising a central conduit moreor less concentric with a nozzle body and forming there between a nozzleannulus. A nozzle insert includes one or more-small diameter passagesthat route fluid or slurry into a central chamber defined by a nozzlehead. One or more swirl plates provide a swirling action to the fluid orslurry passing through this nozzle as the fluid or slurry passes throughan exit orifice. The spray formed may be a more focused spray than thatformed from other nozzles. Pressure-swirl spray nozzles arehigh-performance (small drop size) devices. The stationary core inducesa rotary fluid motion that causes the swirling of the fluid in the swirlchamber. A film is discharged from the perimeter of the outlet orificeproducing a characteristic hollow cone spray pattern. Air or othersurrounding gas is drawn inside the swirl chamber to form an air corewithin the swirling liquid. Many configurations of fluid inlets are usedto produce this hollow cone pattern depending on the nozzle capacity andmaterials of construction. A spill-return pressure-swirl single-fluidnozzle is one variety of pressure swirl nozzle includes a controlledreturn of fluid from the swirl chamber to the feed system. This allowsthe nozzle pressure drop to remain high while allowing a wide range ofoperating rates. Solid cone nozzles produce a “solid” cone spray offluid or slurry by employing a vane-shaped internal region. A swirlingliquid motion is induced with the vane structure, however; the dischargeflow fills the entire outlet orifice. For the same capacity and pressuredrop, a full cone nozzle will produce a larger drop size than a hollowcone nozzle. The coverage is the desired feature for such a nozzle,which is often used for applications to distribute fluid over an area.Compound nozzles, which include two or more types of nozzles, may alsobe suitable. Compound nozzles allow control of drop size and spraycoverage angle.

Suitable multiple-fluid nozzles include both internal-mix multiple fluidnozzles and external-mix multiple-fluid nozzles. One example of aninternal-mix multiple fluid nozzle comprises a nozzle body, a centralconduit, forming there between a nozzle annulus through which flows afirst fluid or slurry. A second fluid or slurry flows though a centralpassage of the central conduit. The central conduit includes a taperedsection, followed by a cylindrical end section that forms an exit forthe central passage. The nozzle body also has a tapered section, whichforces the first fluid or slurry to change course and mix with thesecond fluid or slurry in an internal mixing region. Suitableexternal-mix multiple-fluid nozzles have similar structure tointernal-mix multiple-fluid nozzles, except that central conduit ismoved so that its exit orifice is generally co-planar with the exit endof nozzle body, forming an external mixing zone where the first andsecond fluids or slurries may mix.

As used herein the term “nozzle” includes atomizers, and suitableatomizers that may be used in systems and methods of the presentdisclosure include, but are not limited to, rotary atomizers,electrostatic atomizers, and ultrasonic atomizers. One example of arotary atomizer is described in U.S. Pat. No. 6,578,779. Rotaryatomizers use a high speed rotating disk, cup or wheel to dischargeliquid at high speed to the perimeter, forming a hollow cone spray. Therotational speed controls the drop size. Electrostatic charging ofsprays may be useful for high transfer efficiency. The charging istypically at high voltage (20 to 40 kV) but low current. An example ofsuch a device is illustrated is U.S. Pat. No. 5,011,086.

Ultrasonic atomizer spray nozzles utilize high frequency (20 kHz to 50kHz) vibration to produce narrow drop-size distribution and low velocityspray from a liquid. The vibration of a piezoelectric crystal causescapillary waves on the nozzle surface liquid film. An example of such adevice illustrated schematically in U.S. Pat. No. 4,723,708.

Fluids or slurries may be supplied from one or more supply tanks orcontainers which are fluidly and mechanically connected to thedownstream apparatus via one or more conduits, which may or may notinclude flow control valves. One or more of the conduits may be flexiblemetal hoses, but they may also be solid metal, ceramic, or ceramic-linedmetal conduits. Any or all of the conduits may include a flow controlvalve, which may be adjusted to shut off flow through a particularconduit.

In order to determine which of the many foam embodiments may work bestfor any given situation to stabilize or de-stabilize bubbles in theglass foam may take a small amount of experimentation, but the degree ofexperimentation is not considered to be extensive or undue. Basically,the molten mass of glass and foam is allowed to enter the downstreamapparatus, and one or more of the glass foam stabilization orde-stabilization techniques begun soon thereafter, and tuned to achievethe greatest stabilization or de-stabilization effect on the foam.

In systems and methods employing dropping of particulate solids onto theglass foam, such as embodiment 700 of FIG. 8, one or more hoppers (notillustrated) containing one or more particles or particulate matter maybe provided. One or more hoppers may route particles through roof 4,through sidewall 8, or through both, through various apertures. Hoppersmay be positioned in multiple longitudinal and transverse positions indownstream apparatus. While it is contemplated that that particulatewill flow merely by gravity from the hoppers, and the hoppers need nothave a pressure above the solids level, certain embodiments may includea pressurized headspace above the solids in the hoppers. In embodiments,the teachings of assignee's co-pending application U.S. Ser. No.13/540,704, filed Jul. 3, 2012, describing various screw-feederembodiments, and teaching of feed material compaction may be useful,although in the present methods and systems loss of batch or other feedmaterial is not the primary concern. In fact, in terms of foamde-stabilization, uncompacted batch or other particulate matter may bepreferred. One or more of the hoppers may include shakers or otherapparatus common in industry to dislodge overly compacted solids andkeep the particles flowing. Furthermore, each hopper will have a valveother apparatus to stop or adjust flow of particulate matter into thedownstream apparatus. These details are not illustrated for sake ofbrevity.

Certain systems and methods of the present disclosure may be combinedwith other strategies for foam de-stabilization, if that is the desiredend. For example, adding nitrogen as a treating composition to themolten mass of glass and bubbles in the downstream apparatus may tend tomake bubbles in glass foam 16 less stable when there is the presence ofa high moisture atmosphere in the downstream apparatus. A high moistureatmosphere may exist in the downstream apparatus for example when one ormore high momentum burners (whether oxy/fuel or not) are used asimpingement burners in the downstream apparatus to impinge on glass foam16. The use of one or more high momentum impingement burners (whetheroxy/fuel or not) in a downstream flow channel is described in assignee'sco-pending application U.S. Ser. No. 13/493,170, filed Jun. 11, 2012.

Measuring effectiveness of the foam stabilization or de-stabilizationsystems and methods described herein may generally be made by takingsamples of the molten mass of glass and counting bubbles and their sizein the molten mass, or a solidified or partially solidified samplethereof, using the naked eye. Another naked eye measurement may simplybe comparing an acceptable glass to a glass sample made using a systemand method of the present disclosure, and making a naked eye comparison.More sophisticated methods and equipment may certainly be used, such asimage analysis using computers to measure size, size distribution andquantity of bubbles (or other parameters) within a high-resolutionphotograph or micrograph of the material to be analyzed. For example,companies such as Glass Service market methods and equipment for suchmeasurements. The glass melting method, as well as phenomena within themelt, may be continuously observed, recorded and evaluated using a hightemperature observation furnace equipped with a special silicaobservation crucible. This equipment may be further coupled with imageanalysis equipment to provide easy manipulation of recorded data. Forexample, in a “melt test”, the objective is to evaluate the finingcharacteristics of differing batch compositions. The area of therecorded images occupied by inhomogeneities (bubbles), bubble sizedistribution, bubble number, as well as bubble growth rates vs. meltingtime, may be evaluated to provide comparison between individual batches.The records of the melting course may be provided in the form of videofiles, which may be displayed on a personal computer, handheld computer,or other viewer. Bubble growth rate, or shrinkage rate, or rate ofdisappearance measurements may be based on direct observation andrecording of bubble sizes depending on time. It is possible to keepbubbles suspended in the melt for hours by the developed “shuttle”method.

In embodiments of the present disclosure, a reduction of 5 percent, or10 percent, or 20 percent, or 30 percent or more of foam may beacceptable. In other embodiments, nothing short of complete orsubstantially complete foam or bubble removal will suffice, in otherwords 90 percent, or 95 percent, or 99 percent, or even 99.9 percentreduction in foam and bubbles.

The downstream apparatus may include one or more bushings (notillustrated) for example when producing glass fiber (not illustrated).Downstream apparatus for use in systems and methods of the presentdisclosure may comprise a roof, floor and sidewall structure comprisedof an outer metal shell, non-glass-contact brick or other refractorywall, and glass-contact refractory for those portions expected to be incontact with molten glass. Downstream apparatus may include severalsections arranged in series, each section having a roof, floor, andsidewall structure connecting its roof and floor, and defining a flowchannel for conditioning molten glass flowing there through. Thesections may be divided by a series of skimmers, each extendinggenerally substantially vertically downward a portion of a distancebetween the roof and floor of the channel, with a final skimmerpositioned between a last channel section and a forehearth. The numberof sections and the number of skimmers may each be more or less thantwo. The downstream apparatus may be rectangular as illustrated in thevarious figures, or may be a shape such as a generally U-shaped orV-shaped channel or trough of refractory material supported by ametallic superstructure.

The flow rate of the molten glass through the downstream apparatus(unless it is a holding container without flow) will depend on manyfactors, including the geometry and size of the SCM and downstreamapparatus, temperature of the melt, viscosity of the melt, and likeparameters, but in general the flow rate of molten glass may range fromabout 0.5 lb./min to about 5000 lbs./min or more (about 0.23 kg/min toabout 2300 kg/min or more), or from about 10 lbs./min to about 500lbs./min (from about 4.5 kg/min to about 227 kg/min), or from about 100lbs./min to 300 lbs./min (from about 45 kg/min to about 136 kg/min).

Certain embodiment may use low momentum burners. Low momentum burnersuseful in systems and methods of this disclosure may include some of thefeatures of those disclosed in assignee's U.S. patent application Ser.No. 13/268,130, filed Oct. 7, 2011. For low momentum burners usingnatural gas as fuel, the burners may have a fuel firing rate rangingfrom about 0.4 to about 40 scfh (from about 11 L/hr. to about 1,120L/hr.); an oxygen firing rate ranging from about 0.6 to about 100 scfh(from about 17 L/hr. to about 2,840 L/hr.); a combustion ratio rangingfrom about 1.5 to about 2.5; nozzle velocity ratio (ratio of velocity offuel to oxygen at the fuel nozzle tip) ranging from about 0.5 to about2.5; a fuel velocity ranging from about 6 ft./second to about 40ft./second (about 2 meters/second to about 12 meters/second) and anoxidant velocity ranging from about 6 ft./second to about 40 ft./second(about 2 meters/second to about 12 meters/second).

Those of skill in this art will readily understand the need for, and beable to construct suitable fuel supply conduits and oxidant supplyconduits, as well as respective flow control valves, threaded fittings,quick connect/disconnect fittings, hose fittings, and the like.

Submerged combustion melters may be fed a variety of feed materials. Theinitial raw material may include any material suitable for formingmolten glass such as, for example, limestone, glass, sand, soda ash,feldspar and mixtures thereof. A glass composition for producing glassfibers known as “E-glass” typically includes 52-56% SiO₂, 12-16% Al₂O₃,0-0.8% Fe₂O₃, 16-25% CaO, 0-6% MgO, 0-10% B₂O₃, 0-2% Na₂O+K₂O, 0-1.5%TiO₂ and 0-1% F₂. Other glass compositions may be used, such as thosedescribed in assignee's U.S. Publication Nos. 2007/0220922 and2008/0276652. The initial raw material to provide these glasscompositions can be calculated in known manner from the desiredconcentrations of glass components, molar masses of glass components,chemical formulas of batch components, and the molar masses of the batchcomponents. Typical E-glass batches include those reproduced in Table 1,borrowed from U.S. Publication No. 2007/0220922. Notice that duringglass melting, carbon dioxide (from lime) and water (borax) evaporate.The initial raw material can be provided in any form such as, forexample, relatively small particles.

TABLE 1 A typical E-glass batch BATCH COMPOSITION (BY WEIGHT) Quartz CaSilicate and Ca Limestone Quick- Ca Volcanic & Volcanic Quartz- Quartz-Limestone Ca Silicate Quartz- Clay Silicate/ Raw material (Baseline)lime Silicate Glass Glass free #1 free #2 Slag Slag free #3 FreeFeldspar Quartz (flint) 31.3%  35.9%  15.2%  22.6%  8.5%   0%   0%22.3%  5.7%   0%   0% 19.9%  Kaolin Clay 28.1%  32.3%  32.0%  23.0% 28.2%  26.4%    0% 22.7%  26.0%  26.0%    0%   0% BD Lime 3.4% 4.3% 3.9%3.3% 3.8% 3.7% 4.3% 2.8% 3.1% 3.1% 4.3% 4.4% Borax 4.7% 5.2% 5.2%   0%1.5%   0%   0%   0%   0%   0% 1.1% 1.1% Boric Acid 3.2% 3.9% 3.6% 7.3%6.9% 8.2% 8.6% 7.3% 8.2% 8.2% 7.7% 7.8% Salt Cake 0.2% 0.2% 0.2% 0.2%0.2% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2% Limestone 29.1%   0%   0% 28.7%   0%   0%   0% 27.9%    0%   0%   0%   0% Quicklime   0% 18.3%    0%  0%   0%   0%   0%   0%   0%   0%   0%   0% Calcium   0%   0% 39.9%   0% 39.1%  39.0%  27.6%    0% 37.9%  37.9%  26.5%  26.6%  SilicateVolcanic Glass   0%   0%   0% 14.9%  11.8%  17.0%  4.2% 14.7%  16.8% 16.8%    0%   0% Diatomaceous 5.5% 17.4%    0%   0% 5.7% 20.0%    0%Earth (DE) Plagioclase   0% 38.3%    0%   0%   0% 40.1%  40.1%  FeldsparSlag   0%   0% 2.0% 2.0% 2.0%   0%   0% Total 100%  100%  100%  100% 100%  100%  100%  100%  100%  100%  100%  100%  Volume of 1668 0 0 16470 0 0 1624 0 0 0 0 CO2@ 1400 C.SCMs may also be fed by one or more roll stands, which in turn, supportsone or more rolls of glass mat as described in assignee's co-pendingapplication U.S. Ser. No. 12/888,970, filed Sep. 23, 2010, incorporatedherein by reference. In certain embodiments powered nip rolls mayinclude cutting knives or other cutting components to cut or chop themat (or roving, in those embodiments processing roving) into smallerlength pieces prior to entering the SCM. Also provided in certainembodiments may be a glass batch feeder. Glass batch feeders arewell-known in this art and require no further explanation.

Downstream apparatus may include refractory fluid-cooled panels.Liquid-cooled panels may be used, having one or more conduits or tubingtherein, supplied with liquid through one conduit, with another conduitdischarging warmed liquid, routing heat transferred from inside themelter to the liquid away from the melter. Liquid-cooled panels may alsoinclude a thin refractory liner, which minimizes heat losses from themelter, but allows formation of a thin frozen glass shell to form on thesurfaces and prevent any refractory wear and associated glasscontamination. Other useful cooled panels include air-cooled panels,comprising a conduit that has a first, small diameter section, and alarge diameter section. Warmed air transverses the conduits such thatthe conduit having the larger diameter accommodates expansion of the airas it is warmed. Air-cooled panels are described more fully in U.S. Pat.No. 6,244,197. In certain embodiments, the refractory fluidcooled-panels are cooled by a heat transfer fluid selected from thegroup consisting of gaseous, liquid, or combinations of gaseous andliquid compositions that functions or is capable of being modified tofunction as a heat transfer fluid. Gaseous heat transfer fluids may beselected from air, including ambient air and treated air (for airtreated to remove moisture), inert inorganic gases, such as nitrogen,argon, and helium, inert organic gases such as fluoro-, chloro- andchlorofluorocarbons, including perfluorinated versions, such astetrafluoromethane, and hexafluoroethane, and tetrafluoroethylene, andthe like, and mixtures of inert gases with small portions of non-inertgases, such as hydrogen. Heat transfer liquids may be selected frominert liquids that may be organic, inorganic, or some combinationthereof; for example, salt solutions, glycol solutions, oils and thelike. Other possible heat transfer fluids include steam (if cooler thanthe oxygen manifold temperature), carbon dioxide, or mixtures thereofwith nitrogen. Heat transfer fluids may be compositions comprising bothgas and liquid phases, such as the higher chlorofluorocarbons.

Certain embodiments may comprise a method control scheme for thedownstream apparatus. For example, as explained in the '970 application,a master method controller may be configured to provide any number ofcontrol logics, including feedback control, feed-forward control,cascade control, and the like. The disclosure is not limited to a singlemaster method controller, as any combination of controllers could beused. The term “control”, used as a transitive verb, means to verify orregulate by comparing with a standard or desired value. Control may beclosed loop, feedback, feed-forward, cascade, model predictive,adaptive, heuristic and combinations thereof. The term “controller”means a device at least capable of accepting input from sensors andmeters in real time or near-real time, and sending commands directly toone or more foam de-stabilization elements, and/or to local devicesassociated with foam de-stabilization elements able to accept commands.A controller may also be capable of accepting input from humanoperators; accessing databases, such as relational databases; sendingdata to and accessing data in databases, data warehouses or data marts;and sending information to and accepting input from a display devicereadable by a human. A controller may also interface with or haveintegrated therewith one or more software application modules, and maysupervise interaction between databases and one or more softwareapplication modules. The controller may utilize Model Predictive Control(MPC) or other advanced multivariable control methods used in multipleinput/multiple output (MIMO) systems. As mentioned previously, themethods of assignee's co-pending application U.S. Ser. No. 13/268,065,filed Oct. 7, 2011, using the vibrations and oscillations of the melteritself, may prove useful predictive control inputs.

The downstream apparatus floors and sidewall structures may include aglass-contact refractory lining. The glass-contact lining may be 1centimeter, 2 centimeters, 3 centimeters or more in thickness, however,greater thickness may entail more expense without resultant greaterbenefit. The refractory lining may be one or multiple layers.Glass-contact refractory used in downstream apparatus described hereinmay be cast concretes such as disclosed in U.S. Pat. No. 4,323,718. Twocast concrete layers are described in the '718 patent, the first being ahydraulically setting insulating composition (for example, that knownunder the trade designation CASTABLE BLOC-MIX-G, a product ofFleischmann Company, Frankfurt/Main, Federal Republic of Germany). Thiscomposition may be poured in a form of a wall section of desiredthickness, for example a layer 5 cm thick, or 10 cm, or greater. Thismaterial is allowed to set, followed by a second layer of ahydraulically setting refractory casting composition (such as that knownunder the trade designation RAPID BLOCK RG 158, a product of Fleischmanncompany, Frankfurt/Main, Federal Republic of Germany) may be appliedthereonto. Other suitable materials for the downstream apparatus,components that require resistance to high temperatures, such asparticle guns, rotating blades and paddles, and refractory block burners(if used) are fused zirconia (ZrO₂), fused cast AZS(alumina-zirconia-silica), rebonded AZS, or fused cast alumina (Al₂O₃).The choice of a particular material is dictated among other parametersby the geometry of the downstream apparatus and the foamde-stabilization equipment used, and the type of glass to be produced.

EXAMPLES

Laboratory testing was carried out to evaluate use of atmospheres ofdifferent compositions to influence the foam decay rate and the size ofthe bubbles within the glass foam layer of glass compositions producedfrom an SCM. Nine trial conditions were tested, the details of which aredetailed herein. Videos were made of all trials and bubble sizemeasurements were made of the noted trials.

The experiments were conducted by placing 20 grams of SCM melterdischarge (E-glass) into a quartz tube and placing the tube into apre-heated furnace at 1375° C. The atmosphere inside of the tube,considered to be a reasonable simulation of the conditions inside theatmosphere of an apparatus downstream of an SCM, was controlled byadding gases of specific mixture from a gas mixing and flow controlstation to the top of the tube. The tube was sealed with a hightemperature refractory fiber so that the ambient air was sealed outsidethe tube and only the gases from the mixing and flow control stationwere allowed into the tube. The gases were discharged from the quartztube through a small ceramic tube inserted through the fiber seal. Solidchemicals were added to (dropped onto) the foam surface through the gasdischarge tube for the experiments for adding a solid to the foamsurface.

The nine experimental cases are shown in Table 2.

TABLE 2 Experiments Experiment Number (Example Number) Experiment NameExperimental Conditions 1 (Comparative Base Case Oxy-fuel combustionExample 1) atmosphere (40% CO₂, 2% O₂, 58% H₂O) 2 (Example 1) Dry AirDry air - 19% O₂, 81% N₂ 3 (Example 2) Wet Air Wet air - ambient airsaturated with water up to 70% 4 (Example 3) Base Case with SO₂ Basecase atmosphere with 1 mole % SO₂ added 5 (Example 4) Base Case withSO₂/ Base case atmosphere with O₂ a mixture of SO₂ and O₂, molar rationof 2:1 SO2 to O₂, 50 ml/min bubbled below the glass for 10 minutes. 6(Example 5) Base Case with Base case with 0.1 gram of sodium sulfate andNa₂SO₄ diluted with 0.5 cullet mixture gram of processed E-glass culletadded to the top of the foam at the 45 min. mark of the test 7(Comparative Repeat Base Case Same as 1 Example 2) 8 (Example 6) Basecase with cullet Base case atmosphere, followed by sodium plus adding0.6 gram of sulfate processed basement cullet added to the top of thefoam after 45 minutes of test time, followed about 10 minutes later byadding 0.1 gram of Na₂SO₄ to the top of the foam 9 (Example 7) Basecase/fully Base case atmosphere fully saturated saturated with water

Experiment 1, called the Base Case, simulated the expected atmosphereabove the SCM glass in a refractory channel downstream of the SCM, wherethe channel is heated with oxy-fuel firing with natural gas, providingan atmosphere of CO₂, O₂, and water vapor in the concentrationsindicated in Table 2. Videos were made of each experimental trial caseand measurements completed for the amount of clear glass at the bottomof the glass and the height of foam on top of the glass. Changes inthese measurements over the duration of each test give the rate offining and foam decay rate. Bubbling SO₂ gas through the glass or addingSO₂ to the atmosphere above the glass had little effect on the foamdecay, and therefore was deemed to stabilize the foam. FIGS. 16A-G,17A-C, and 18A-E illustrate graphically some experimental results inaccordance with these experiments.

FIGS. 16A and 16B illustrate graphically the influence of water vapor onfoam level and glass level, and summarize the results of Experiments 1,2, 3, and 9 (Comparative Example 1, Example 1, Example 2, and Example7). FIG. 16A illustrates foam level and glass level as a function oftime for the four conditions represented in these examples, while FIG.16B illustrates foam height as a function of time for these fourexperiments.

Example 1 (Dry Air), referencing FIG. 16C: compared with the Base Casethe following observations were made: 1) there was no formation of hugebubbles, and 2) foam decay rate was very gradual, there was a very long“tail”, in that even after three hours there was still some foampresent.

Example 2 (Wet Air), referencing FIG. 16D: compared with the Base Casethe following observations were made: 1) similar to the Base Case, largebubbles were formed; 2) the foam level and foam height decreased morerapidly, indicating that water in the atmosphere had a significantimpact to increase the foam decay rate, and the diffusion of water intothe bubbles, resulting in larger bubbles; and 3) “foam free” glass wasobtained after about two hours. In light of these test results, themechanism of bubble de-stabilization and breakage appeared to be thatthe partial pressure of water (ppH₂O), being higher on the outside ofthe bubbles than inside the bubbles, caused the water to diffuse intothe bubbles making them grow larger and resulting in thinner glassbubble layers that were easier to break. The evidence for this was themeasurement of larger bubbles in the tests where the ppH₂O was higher.The effectiveness of this was better than expected from discussions withothers and from the literature.

Example 7 (Base Case/fully saturated), referencing FIGS. 16E and 16F:compared with the Base Case the following observations were made: 1)foam level and foam height decreased very rapidly (compare FIG. 16E,after 30 minutes, with FIG. 16F, after 40 minutes); 2) foam decay ratewas also much faster compared to the Example 2 (Wet Air), which wassurmised to be a combined effect of a) faster bubbles growth, and b)water droplets falling on the foam surface; and 3) “foam free” glass wasobtained after only 40 minutes. The effectiveness of water dropsimpinging on the foam was much greater than expected. We expected thatdropping water drops onto the foam would just have the effect ofdecreasing the bubble size due to cooling the gases inside the bubbles,with the bubbles simply returning to the original size once the waterevaporated and the gases reheated. This did not happen.

FIGS. 17A and 17B illustrate graphically the influence of sulfur dioxideand a mixture of sulfur dioxide and oxygen on foam level and glasslevel, and summarize the results of Experiments 4 and 5 (Examples 3 and4). FIG. 17A illustrates foam level and glass level as a function oftime for the Base Case and the two conditions represented in Examples 3and 4, while FIG. 17B illustrates foam height as a function of time forthe Base Case and Examples 3 and 4.

Examples 3 and 4, Influence of Sulfur Dioxide Gas, referencing FIG. 17C:as may be seen, addition of SO₂ in the atmosphere (1 molar percent SO₂)or by bubbling (in combination with oxygen) did not result in a fasterfoam decay rate of the foam height. Even after three hours there wasstill some foam (FIG. 17C). Thus, these compositions in the atmosphereof an apparatus downstream of an SCM would tend to stabilize the foamlayer, and lead to production of foamed glass products.

FIGS. 18A and 18B illustrate graphically the influence of dropping amixture of sodium sulfate and cullet on foam level and glass level(Example 5), and the influence of first dropping cullet, then sodiumsulfate onto the foam (Example 6) on foam level and glass level, andsummarize the results of Experiments 6 and 8 (Examples 5 and 6). FIG.18A illustrates foam level and glass level as a function of time for theBase Case and the two conditions represented in Examples 5 and 6, whileFIG. 18B illustrates foam height as a function of time for the Base Caseand Examples 5 and 6.

Examples 5 and 6, Influence of Sodium Sulfate and Cullet, referencingFIGS. 18C, 18D, and 18E: as may be seen, addition of a mixture of sodiumsulfate and cullet on the foam surface resulted in a temporary smallerfoam height, and subsequently gases were produced resulting in more foamproduction; in the final stage (tail) of the experiment some largerbubbles were created and observed (FIG. 18C), these bubbles disturbedthe foam level measurement (resulting in a stable foam level of about 7mm). Omitting the larger bubbles, a foam free melt was obtained withinabout 1 one hour (after introducing the sodium sulfate/cullet mixture ontop of the melt).

In Example 6, where cullet was first applied to the foam, then sodiumsulfate, the following observations were made: 1) the addition of culletresulted in disturbance of the foam, and the foam level decreased; 2)with addition of pure sodium sulfate the foam disappeared almostinstantaneously (within 2-3 minutes, perhaps after melting of the sodiumsulfate, compare FIG. 18D, taken 2 minutes prior to addition of sodiumsulfate to the foam, with FIG. 18E, taken 3 minutes after addition ofsodium sulfate to the foam); and 3) due to the addition of sodiumsulfate, some growth of bubbles was observed in the top layer of themelt, resulting in limited foam height growth.

Those having ordinary skill in this art will appreciate that there aremany possible variations of the systems and methods described herein,and will be able to devise alternatives and improvements to thosedescribed herein that are nevertheless considered to be within theclaims.

What is claimed is:
 1. A method comprising: flowing a molten mass offoamed glass comprising molten glass and bubbles entrained therein intoan apparatus downstream of a submerged combustion melter, the downstreamapparatus comprising a floor, a roof, and a sidewall structureconnecting the floor and roof, the foamed glass having glass foamcomprising glass foam bubbles on at least a portion of a top surface ofthe foamed glass, the downstream apparatus defining a space for agaseous atmosphere above and in contact with the glass foam; heating ormaintaining temperature of the foamed glass in the downstream apparatus;and controlling bubble size of the glass foam bubbles in the foamedglass by controlling composition of the atmosphere above the glass foamin the downstream apparatus.
 2. The method of claim 1 wherein thecontrolling composition of the atmosphere comprises mixing dry ambientair or dry synthetic air into the atmosphere from a source outside ofthe downstream apparatus.
 3. The method of claim 1 wherein thecontrolling composition of the atmosphere comprises mixing ambient airhaving humidity above that of dry air into the atmosphere from a sourceoutside of the downstream apparatus.
 4. The method of claim 1 whereinthe controlling composition of the atmosphere comprises mixing dryambient air or dry synthetic air into the atmosphere from a sourceoutside of the downstream apparatus, and wherein the heating ormaintaining temperature comprises combusting an oxidant with a fuel toproduce combustion products, so that the combustion products also mixwith the atmosphere, wherein the oxidant is selected from the groupconsisting of ambient air, synthetic air, oxygen-enriched ambient air,oxygen-enriched synthetic air, and compositions comprising more thanabout 95 mole percent oxygen.
 5. The method of claim 1 wherein thecontrolling composition of the atmosphere comprises mixing dry ambientair or dry synthetic air with the atmosphere from a first source outsideof the downstream apparatus, and spraying water vapor and/or steam intothe atmosphere from a second source outside of the downstream apparatus.6. The method of claim 1 wherein the heating or maintaining temperatureof the foamed glass in the downstream apparatus is devoid of electricalheating, and comprises using one or more non-submerged oxy-fuelcombustion burners positioned in corresponding apertures in the sidewallstructure and/or the roof of the downstream apparatus, the non-submergedoxy-fuel combustion burners producing combustion products contributingto control of the atmosphere above the glass foam.
 7. The method ofclaim 6 comprising spraying water vapor and/or steam into the atmospherefrom a first source outside of the downstream apparatus.
 8. The methodof claim 7 comprising dripping liquid water onto the glass foam from asecond source outside of the downstream apparatus.
 9. The method ofclaim 5 comprising adding a chemical to the water spray and/or steamfrom a third source outside of the downstream apparatus.
 10. The methodof claim 7 comprising adding a chemical to the water spray and/or steamfrom a second source outside of the downstream apparatus.
 11. The methodof claim 8 comprising adding a chemical to the water spray and/or steamfrom a third source outside of the downstream apparatus.
 12. The methodof claim 6 wherein the controlling of the composition of the atmosphereabove the glass foam comprises injecting a non-combustion compositioninto at least a portion of the atmosphere from a source outside of thedownstream apparatus using one or more apparatus positioned in one ormore apertures the sidewall structure and/or the roof.
 13. The method ofclaim 12 wherein the non-combustion composition comprises 10 molepercent of an oxygenated sulfur compound or less.
 14. The method ofclaim 13 wherein the non-combustion composition comprises 1 mole percentof the oxygenated sulfur compound or less.
 15. The method of claim 6comprising adding a chemical to at least a portion of the glass foamfrom a source outside of the downstream apparatus through one or moreapertures in the roof and/or sidewall structure by adding the chemicalto a water spray as a slurry, emulsion, or dissolved in the water, oradding the chemical to a flow of steam.
 16. The method of claim 15wherein the chemical comprises one or more compounds selected from thegroup consisting of alkali metal chalcogens.
 17. The method of claim 6comprising dripping a liquid or dropping a solid composition from asource outside of the downstream apparatus onto at least a portion ofthe glass foam through one or more apertures in the roof and/or sidewallstructure.
 18. The method of claim 17 wherein the solid compositioncomprises one or more compounds selected from the group consisting ofalkali metal chalcogens, alkali metal carbonates, alkaline earthcarbonates, and mixtures and combination of two or more of these.
 19. Amethod comprising: flowing a molten mass of foamed glass comprisingmolten glass and bubbles entrained therein into an apparatus downstreamof a submerged combustion melter, the downstream apparatus comprising afloor, a roof, and a sidewall structure connecting the floor and theroof, the foamed glass having glass foam comprising glass foam bubbleson at least a portion of a top surface of the foamed glass, thedownstream apparatus defining a space for a gaseous atmosphere above andin contact with the glass foam; heating or maintaining temperature ofthe foamed glass using only combustion heating comprising one or morenon-submerged oxy-fuel combustion burners positioned in the sidewallstructure and/or the roof of the downstream apparatus, the non-submergedoxy-fuel combustion burners contributing to production of the atmosphereabove the glass foam; and controlling bubble size of the foam glassbubbles by bubbling a composition comprising an oxygenated sulfurcompound and optionally oxygen below a level of the foamed glass in thedownstream apparatus, thereby stabilizing size of the glass foam bubblesand a foam decay rate, with the proviso that if oxygen is present in thecomposition, the molar ratio of oxygenated sulfur compound to oxygenranges from about 3:1 to about 0.5:1.
 20. The method of claim 19 whereinthe molar ratio of oxygenated sulfur compound to oxygen ranges fromabout 2.5:1 to about 1.5:1.
 21. The method of claim 20 wherein the molarratio of oxygenated sulfur compound to oxygen is about 2:1.
 22. A methodcomprising: flowing a molten mass of foamed glass comprising moltenglass and bubbles entrained therein into an apparatus downstream of asubmerged combustion melter, the downstream apparatus comprising afloor, a roof, and a sidewall structure connecting the floor and theroof, the foamed glass having glass foam comprising glass foam bubbleson at least a portion of a top surface of the foamed glass, thedownstream apparatus defining a space for a gaseous atmosphere above andin contact with the glass foam; heating or maintaining temperature ofthe foamed glass in the downstream apparatus; and controlling a foamdecay rate of the glass foam bubbles by: i) adjusting composition of atleast a portion of the gaseous atmosphere; or ii) contacting a topsurface of the glass foam with a liquid or solid composition orcombination thereof; or iii) combination of (i) and (ii).
 23. The methodof claim 22 wherein the adjusting composition of the gaseous atmospherecomprises mixing dry ambient air or dry synthetic air into the gaseousatmosphere from a source outside of and fluidly connected to thedownstream apparatus.
 24. The method of claim 22 wherein the adjustingcomposition of the gaseous atmosphere comprises mixing ambient air orsynthetic air having humidity above that of dry air from a sourceoutside of and fluidly connected to the downstream apparatus.
 25. Themethod of claim 22 wherein the adjusting composition of the gaseousatmosphere comprises mixing dry ambient air or dry synthetic air intothe gaseous atmosphere from a source outside of and fluidly connected tothe downstream apparatus, and wherein the heating or maintainingtemperature comprises combusting an oxidant with a fuel to producecombustion products so that the combustion products mix with the gaseousatmosphere, wherein the oxidant is selected from the group consisting ofambient air, synthetic air, oxygen-enriched ambient air, oxygen-enrichedsynthetic air, and compositions comprising more than about 95 molepercent oxygen.
 26. The method of claim 22 wherein the adjustingcomposition of the gaseous atmosphere comprises mixing dry ambient airor dry synthetic air with the gaseous atmosphere from a first sourceoutside of and fluidly connected to the downstream apparatus, andspraying water vapor and/or steam into the gaseous atmosphere from asecond source outside of and fluidly connected to the downstreamapparatus.
 27. The method of claim 22 wherein the heating or maintainingtemperature of the foamed glass in the downstream apparatus comprisesusing combustion heating only comprising one or more non-submergedoxy-fuel combustion burners positioned in corresponding apertures in thesidewall structure and/or the roof of the downstream apparatus, thenon-submerged oxy-fuel combustion burners contributing to the productionof the gaseous atmosphere above the glass foam.
 28. The method of claim27 wherein the adjusting composition of the gaseous atmosphere comprisesspraying water vapor and/or steam into the gaseous atmosphere from asource outside of and fluidly connected to the downstream apparatus. 29.The method of claim 28 comprising dripping liquid water onto the topsurface of the glass foam from a source outside of and fluidly connectedto the downstream apparatus.
 30. The method of claim 26 wherein thecontacting of the top surface of the glass foam with a liquid or solidcomposition or combination thereof comprises adding a chemical to thewater vapor spray as a slurry, emulsion, or dissolved in the water, oradding the chemical to the steam, from a third source outside of andfluidly connected to the downstream apparatus.
 31. The method of claim28 wherein the contacting of the top surface of the glass foam with aliquid or solid composition or combination thereof comprises adding achemical to the water vapor spray as a slurry, emulsion, or dissolved inthe water, or adding the chemical to the steam, from a second sourceoutside of and fluidly connected to the downstream apparatus.
 32. Themethod of claim 29 wherein the contacting of the top surface of theglass foam with a liquid or solid composition or combination thereofcomprises adding a chemical to the water spray as a slurry, emulsion, ordissolved in the water, or adding the chemical the steam, from a secondsource outside of and fluidly connected to the downstream apparatus. 33.The method of claim 28 wherein the spraying of the water vapor or thesteam into the gaseous atmosphere increases water content of theatmosphere above 58 percent saturation.
 34. The method of claim 33wherein the water content of the gaseous atmosphere is increased to 100percent saturation.
 35. The method of claim 28 wherein the contacting ofthe top surface of the glass foam with a liquid or solid composition orcombination thereof comprises dripping liquid water onto at least aportion of the top surface of the glass foam from a second sourceoutside of and fluidly connected to the downstream apparatus.
 36. Themethod of claim 26 wherein the contacting of the top surface of theglass foam with a liquid or solid composition or combination thereofcomprises dropping solid particles onto at least a portion of the topsurface of the glass foam from a third source outside of and fluidlyconnected to the downstream apparatus.
 37. The method of claim 28wherein the contacting of the top surface of the glass foam with aliquid or solid composition or combination thereof comprises droppingsolid particles onto at least a portion of the top surface of the glassfoam from a second source outside of and fluidly connected to thedownstream apparatus.
 38. The method of claim 29 wherein the contactingof the top surface of the glass foam with a liquid or solid compositionor combination thereof comprises dropping solid particles onto at leasta portion of the top surface of the glass foam from a second sourceoutside of and fluidly connected to the downstream apparatus.
 39. Themethod of claim 22 wherein the solid particles are selected from thegroup consisting of: i) glass particles having the same or similarcomposition as the foamed glass, ii) one or more compounds selected fromthe group consisting of alkali metal chalcogens, alkali metalcarbonates, alkaline earth carbonates, and mixtures and combinationsthereof; and iii) mixtures of (i) and (ii).
 40. The method of claim 39wherein the alkali metal chalcogens are selected from the groupconsisting of alkali metal sulfates, alkali metal bisulfates, alkalimetal sulfites, alkali metal persulfates, alkali metal selenates, alkalimetal tellurates, mixtures of two or more of these, and salts of two ormore of these.
 41. The method of claim 40 wherein the alkali metalchalcogens are selected from the group consisting of sodium sulfate,sodium bisulfate, sodium sulfite, sodium persulfate, sodium selenite,sodium tellurate, lithium sulfate, potassium sulfate, rubidium sulfate,caesium sulfate, double salts of two of these, and double salts of oneof these with another compound.
 42. The method of claim 27 wherein thecontacting of the top surface of the glass foam with the liquid or solidcomposition or combination thereof comprises dropping a mixture of thealkali metal chalcogen particles and the glass particles onto at least aportion of the top surface of the glass foam from a source outside ofand fluidly connected to the downstream apparatus.
 43. The method ofclaim 27 wherein the contacting of the top surface of the glass foamwith the liquid or solid composition or combination thereof comprisesfirst dropping the glass particles onto the glass foam from a firstsource outside of and fluidly connected to the downstream apparatus toform a modified glass foam, followed by dropping the alkali metalchalcogen particles onto at least a portion of the modified glass foamfrom the first source or from a second source outside of and fluidlyconnected to the downstream apparatus.
 44. A method comprising: flowinga molten mass of foamed glass comprising molten glass and bubblesentrained therein into an apparatus downstream of a submerged combustionmelter, the downstream apparatus comprising a floor, a roof, and asidewall structure connecting the floor and roof, the foamed glasshaving glass foam comprising glass foam bubbles on at least a portion ofa top surface of the foamed glass, the downstream apparatus defining aspace for a gaseous atmosphere above and in contact with the glass foam;heating or maintaining temperature of the foamed glass in the downstreamapparatus using only combustion heating comprising one or morenon-submerged oxy-fuel combustion burners positioned in correspondingapertures in the sidewall structure and/or the roof of the downstreamapparatus, the non-submerged oxy-fuel combustion burners producingcombustion products contributing to formation of the atmosphere abovethe glass foam; and increasing foam decay rate of the glass foam bubblesby dropping a mixture of alkali metal chalcogen particles and glassparticles through the gaseous atmosphere and onto at least a portion ofthe glass foam from one or more sources outside of and fluidly connectedto the downstream apparatus, the glass particles having same or similarcomposition as the foamed glass.
 45. A method comprising: flowing amolten mass of foamed glass comprising molten glass and bubblesentrained therein into an apparatus downstream of a submerged combustionmelter, the downstream apparatus comprising a floor, a roof, and asidewall structure connecting the floor and roof, the foamed glasshaving glass foam comprising glass foam bubbles on at least a portion ofa top surface of the foamed glass, the downstream apparatus defining aspace for a gaseous atmosphere above and in contact with the glass foam;heating or maintaining temperature of the foamed glass in the downstreamapparatus using only combustion heating comprising one or morenon-submerged oxy-fuel combustion burners positioned in correspondingapertures in the sidewall structure and/or the roof of the downstreamapparatus, the non-submerged oxy-fuel combustion burners producingcombustion products contributing to formation of the atmosphere abovethe glass foam; and increasing foam decay rate of the glass foam bubblesby fully saturating the gaseous atmosphere with water by injecting awater vapor spray and/or steam from a first source outside of andfluidly connected to the downstream apparatus, and dripping waterthrough the gaseous atmosphere and onto at least a portion of the glassfoam from a second source outside of and fluidly connected to thedownstream apparatus.
 46. A system comprising: an apparatus comprising afloor, a roof, and a sidewall structure connecting the floor and theroof, the floor and sidewall structure defining a first internal spaceconfigured to contain a flowing or non-flowing molten mass of foamedglass comprising molten glass and bubbles entrained therein, the moltenmass having glass foam comprising glass foam bubbles on at least aportion of a top surface of the molten mass, the roof and sidewallstructure defining a second space for a gaseous atmosphere above and incontact with the glass foam; one or more components in and/or protrudingthrough one or more of the floor, roof, and sidewall structureconfigured to heat or maintaining temperature of the foamed glass; oneor more apertures in the sidewall structure and/or the roof foradmitting one or more compositions into the second space; and one ormore sources of the compositions fluidly connected to the apertures. 47.The system of claim 46 wherein the one or more sources of thecomposition comprises a source of dry ambient air or dry synthetic air.48. The system of claim 46 wherein the one or more sources of thecomposition comprises one or more fans blowing ambient air into thegaseous atmosphere.
 49. The system of claim 46 wherein the one or moresources of the composition comprises a source of dry ambient air or drysynthetic air, and wherein the one or more components configured to heator maintaining temperature of the foamed glass comprises one or morecombustion burners combusting an oxidant with a fuel to producecombustion products, so that the combustion products also mix with thegaseous atmosphere, wherein the oxidant is selected from the groupconsisting of ambient air, synthetic air, oxygen-enriched ambient air,oxygen-enriched synthetic air, and compositions comprising more thanabout 95 mole percent oxygen
 50. The system of claim 46 wherein the oneor more sources of the composition comprises a source of dry ambient airor dry synthetic air from outside of the apparatus, and a source ofwater connected to one or more spray nozzles for spraying water vaporand/or steam into the gaseous atmosphere from outside of the apparatus.51. The system of claim 46 wherein the one or more components configuredto heat or maintaining temperature of the foamed glass comprises one ormore non-submerged oxy-fuel combustion burners positioned in one or moreof the apertures producing oxy-fuel combustion products.
 52. The systemof claim 51 wherein the one or more sources of the composition furthercomprises one or more spray nozzles for spraying water vapor and/orsteam into the gaseous atmosphere from outside of the apparatus.
 53. Thesystem of claim 52 wherein the one or more sources of the compositionfurther comprises one or more sources of dripping liquid waterconfigured to drip the liquid water through the gaseous atmosphere andthen onto the glass foam.
 54. The system of claim 50 wherein the one ormore sources of the composition further comprises one or more sources ofa chemical configured to add the chemical to the water spray and/orsteam.
 55. The system of claim 51 wherein the one or more sources of thecomposition further comprises one or more sources of a chemicalconfigured to add the chemical to the water spray and/or steam.
 56. Thesystem of claim 52 wherein the one or more sources of the compositionfurther comprises one or more sources of a chemical configured to addthe chemical to the water spray as a slurry, emulsion, or dissolved inthe water, or adding the chemical to a flow of steam.
 57. The system ofclaim 51 wherein the one or more sources of the composition furthercomprises a source of a non-combustion composition configured to add thenon-combustion composition to the gaseous atmosphere from a sourceoutside of the apparatus.
 58. The system of claim 51 wherein the one ormore sources of the composition comprises a source of a dripping liquidor a dropping solid composition from a source outside of the apparatusthrough the gaseous atmosphere and onto at least a portion of the glassfoam through one or more of the apertures in the roof and/or sidewallstructure.
 59. A system comprising: an apparatus comprising a floor, aroof, and a sidewall structure connecting the floor and the roof, thefloor and sidewall structure defining a first internal space configuredto contain a flowing or non-flowing molten mass of foamed glasscomprising molten glass and bubbles entrained therein, the molten masshaving glass foam comprising glass foam bubbles on at least a portion ofa top surface of the molten mass, the roof and sidewall structuredefining a second space for a gaseous atmosphere above and in contactwith the glass foam; one or more non-submerged oxy-fuel combustionburners positioned in the sidewall structure and/or the roof of theapparatus for heating or maintaining temperature of the foamed glassusing only combustion heating, the non-submerged oxy-fuel combustionburners contributing to production of the gaseous atmosphere; one ormore apertures in the floor and/or sidewall structure; and one or moreconduits fluidly connected to the apertures and configured to introducea composition comprising an oxygenated sulfur compound and optionallyoxygen below a level of the foamed glass in the apparatus, therebystabilizing size of the glass foam bubbles and a foam decay rate, withthe proviso that if oxygen is present in the composition, the one ormore conduits are configured to introduce the composition having a molarratio of oxygenated sulfur compound to oxygen ranging from about 3:1 toabout 0.5:1.